The TV star posted the snapshot to his Twitter page and his Peter Andre Channel accompanied with the caption, "Awww:) look what I caught Embles reading :))"
The image showed 23-year-old medical student Emily reading a book which had the words 'having a healthy pregnancy' on the back cover.
She wore a form-fitting black dress which showed off her rounded tummy for the natural shot.
With her long brunette locks in loose waves, Peter's leading lady kept her head shyly turned away from the camera.
Emily and Peter announced that they were expecting their first baby back in July.
Last week, the Mysterious Girl singer discussed baby names revealing that he prefers biblical and regal ones.
"Biblical names are great," the singer and TV personality said. "Alexandra, Cleopatra, those nice biblical names."
The 40-year-old also said he likes regal names like Elizabeth.
He gave the name suggestions to a pregnant fan who asked him what she should call her baby in a clip on his Peter Andre channel.
The lovable father-of-two explained that it would become clear what to name the child once he or she is born.
"The honest advice I'd give is that if you haven't decided on a name, when that beautiful baby is born you're just going to know, you're going to look at her and you're just going to know."
The pair have been dating for over a year and will welcome their first child together in 2014.
The Australian singer is already a father to two children — son Junior, eight, and daughter Princess Tiaamii, six — from his marriage to Katie Price.
He met Emily through her surgeon father , who operated on Peter in 2010 to remove kidney stones.